<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var arr = new Array(30);
        var sum = 0;
        var a =1;
        var rseult = [];
        for(var i=0;i <30;i++){
            arr[i] = 6;
            if(a%5){
                sum += arr[i];
            } else{
                rseult.push((sum +arr[i])/5)
                sum = 0;
            }
            a++;
        }
        console.log(rseult);
    </script>
</body>
</html>